1. Field of the Invention
Embodiments of the invention relate to flow pattern transition pipes used in pneumatic conveyance systems and, more particularly, to flow pattern transition pipes used in pneumatic conveyance systems to transfer an instable flow pattern to a relatively stable flow pattern.
2. Description of Related Art
Pneumatic conveyance systems are usually used to transport powder such as rice, cement, and ash from one place to another place, in which conditions conveyance capability is the most important parameter. However, in some other situations, for example, when pneumatic conveyance systems are used to convey solid feed in gasification systems, such as coal gasification systems, conveyance stability is as important as conveyance capability, because an instable conveyance may bring serious problems, such as overheat, to gasifiers.
One main factor that affects the conveyance stability is the flow pattern in the pipeline. In dense phase pneumatic conveyance, plug flows or dune flows lead to instable flow patterns, whereas uniform flows lead to stable flow patterns. In gasification systems, solid feed discharged from a feed vessel tends to form plug flows, in which the solid feed comprises both high concentration parts and low concentration parts, and therefore is extremely instable.
Therefore, there is a need to transfer an instable flow pattern to a relatively stable flow pattern in pneumatic conveyance systems.